Derek smiled as Isaac tried to fuck himself back further on Stiles' cock, and held onto the boy's hips, holding him steady, and lining up his own cock, in preparation. "S'good boy," he murmured, approving. "Should've done this sooner...love watching you take cock. Take it so good, Isaac."
He nipped at Stiles' shoulder, marking him in a way he couldn't to the werewolf. "You enjoying yourself, Stiles? The way his hole is greedy for it? You could stay perfectly still, and he'd fuck himself on your cock, he wants it so badly."